One of the most persistent is the episode in Alice in Wonderland which people will always call The Mad Hatter's Tea Party. It is never called that in the book, because it isn't the Hatter's party at all, but the March Hare's -- at the end of the previous chapter, Alice, told by the Cheshire Cat that in one direction lives a Hatter and in the other a March Hare who are both mad, has decided to visit the Hare, as she had seen Hatters before. The chapter in which the tea party occurs is simply called "A Mad Tea Party". Yet people will insist on calling it, as I say above, 'The Mad Hatter's Tea Party'. The language maven Nigel Rees, to whom I once pointed this out, agreed, but suggested it was probably due to the fact that the Hatter has the more prominent speaking role, saying much more than the Hare. But I still think this qualifies as one of the great uncorrectable common errors.

(BTW, I do love Carroll's ésprit in inventing a mad creature called a March Hare to go with the Hatter, on the analogy of the two traditional similes, 'As mad as a hatter', predicated on the occasional effects of the mercury used in hat-making, and 'As mad as a March hare', referring to the behaviour of hares in their Spring rutting season. There is, of course, no such specific creature as 'a March Hare'! Several people to whom I have pointed out that the designation is Carroll's invention have said they had never realised this.)

Any other examples of this sort of persistent error to which people seem so dedicated that, if you point it out, they do not wish to know, thank you?

~Michael~